Effects of Polysaccharide from Polygala fallax on Apoptosis of B16 Melanoma

[Objectives] The paper was to study the effects of polysaccharide from Polygala fallax on apoptosis of B16 melanoma and its mechanism. [Methods] P. fallax polysaccharide was prepared by water extraction and alcohol precipitation method combined with Sevag method. The effects of different concentrations of P. fallax polysaccharide on B16 cell proliferation were detected by MTT assay. Apoptosis was detected by Hoechst 33258 staining assay and flow cytometry. The expressions of Bcl-2, Bax, Cleaved Caspase-3 mRNA were detected by Real-time PCR assay. The expressions of Bcl-2, Bax, Caspase-3, Caspase-8, Caspase-9, Cleaved Caspase-3, Cleaved Caspase-9, ERK, p-ERK, JNK, p-JNK proteins were detected by Western Blot assay. [Results] P. fallax polysaccharide inhibited the cell proliferation of B16 melanoma in a concentration-dependent manner(24 h IC50=0. 213 3 mg/L; 48 h IC50=0.084 89 μg/mL). P. fallax polysaccharide up-regulated the expressions of Bax, Cleaved Caspase-3 mRNA and protein, down-regulated the expressions of Bcl-2 mRNA and protein, activated Caspase-3, Caspase-8 and Caspase-9, and decreased the levels of p-ERK/ERK and p-JNK/JNK. [Conclusions] P. fallax polysaccharide can inhibit the cell proliferation of B16 melanoma and induce their apoptosis, probably attributed to the regulation of MAPK, Bcl-2 and Caspase family signaling pathways.